fixed bug in non yet used unique() method: data was not returned, use client_api when passed a context, make more extraneous API private to avoid confusing developers with cluttered API
fixed bug in non yet used unique() method: data was not returned, use client_api when passed a context, make more extraneous API private to avoid confusing developers with cluttered API

dperini/nwmatcher,dperini/nwmatcher,dperini/nwmatcher